Seasonal changes of gonadotropin-releasing hormone in the Atlantic hagfish Myxine glutinosa

To investigate seasonal reproduction in Myxine glutinosa, we measured total brain gonadotropin-releasing hormone (GnRH) and determined gonadal stages of hagfish collected from the Gulf of Maine once a month for 12 months. Thirty hagfish from each of three different size classes of small (20-35 cm), medium (35-45 cm), and large (50-60+ cm) were sampled for brains and gonads. In the medium and large class hagfish there was an increase in GnRH concentrations during April and May that correlated with male and female gonadal maturity. Also in these size classes of female hagfish, there was a similar rise in GnRH in November and then again in January that preceded the highest incidence of large eggs (stage 7). The elevated GnRH may be influencing the onset of ovarian recrudescence which has been shown in other vertebrates. These data suggest an association of the concentration of brain GnRH with gonadal maturity and provide supportive evidence of a possible seasonal reproductive cycle in M. glutinosa shown in recent studies of [J. Exp. Zool. 301 A (2004) 352], correlating steroid production with gonadal maturation. (C) 2004 Elsevier Inc. All rights reserved

An abundance of Epsilonproteobacteria revealed in the gut microbiome of the laboratory cultured sea urchin, Lytechinus variegatus

In this study, we have examined the bacterial community composition in the laboratory cultured sea urchin Lytechinus variegatus gut microbiome and its culture environment using NextGen amplicon sequencing of the V4 segment of the 16S rRNA gene, and downstream bioinformatics tools. Overall, the gut and tank water was dominated by Proteobacteria, whereas the feed consisted of a co-occurrence of Proteobacteria and Firmicutes at a high abundance. The gut tissue represented Epsilonproteobacteria as dominant, with order Campylobacterales at the highest relative abundance (>95%). However, the pharynx tissue was dominated by class Alphaproteobacteria. The gut digesta and egested fecal pellets had a high abundance of class Gammaproteobacteria, from which Vibrio was found to be the primary genus, and Epsilonproteobacteria, with genus Arcobacter occurring at a moderate level. At the class level, the tank water was dominated by Gammaproteobacteria, and the feed by Alphaproteobacteria. Multi-Dimensional Scaling analysis showed that the microbial community of the gut tissue clustered together, as did the pharynx tissue to the feed. The gut digesta and egested fecal pellets showed a similar relationship to the tank water. Further analysis of Campylobacterales at a lower taxonomic level using the oligotyping method revealed 37 unique types across the ten samples, where Oligotype 1 was primarily represented in the gut tissue. BLAST analysis identified Oligotype 1 to be Arcobacter sp., Sulfuricurvum sp., and Arcobacter bivalviorum at an identity level >90%. This study showed that although distinct microbial communities were evident across multiple components of the sea urchin gut ecosystem, there is a noticeable correlation between the overall microbial communities of the gut with the sea urchin L. variegatus culture environment

Morphological changes, reduction in cell diameter, permeability increase and disruption of intercellular junctions induced by CE.

<p>(A) Gills of zebrafish were exposed to either CE (150 ppm) or held as controls for 24 hours or 56 hours and stained with H&E. Digital micrographs were obtained at 20 x magnifications. Arrows point to edema and blebbing of gill epithelium. The ratios of gill area/gill length were calculated using Image Software (NIH, Bethesda, MD, USA) and presented as 1-dimensional area measurements. Data is quantified and shown as mean ± SD of three independent experiments. ** <i>p</i> < 0.01 vs control by a one-way ANOVA with HSD test. (B) Cell diameter measurements. BEAS-2B cells were grown to confluence in 65 mm dishes and exposed to 0 to 150 ppm of CE for 2 hours (n = 3). Data are shown as a mean ± SD. * <i>p</i> < 0.05 and ** <i>p</i> < 0.01 vs control by a one-way ANOVA with HSD test. (C) Permeability measurement of the bronchial epithelium of the airway. The sub-acute response to CE exposure was modeled by ECIS. BEAS-2B cells were seeded into the ECIS array. Cells were allowed to cover the gold electrodes in each well of the array prior to exposure to CE (0 ppm to 70 ppm). Real-time measurements of the electric resistance of the bronchial epithelial monolayers were obtained at 64 kHz. Resistance measurements were normalized with respect to the values in each well 1 hour prior to the initiation of the exposure. This time period corresponded to 16 hours after the seeding of the cells and was designated as t = 0 hour in the graph. The data are representative of three independent experiments. (D) BREA-2B cells were culture with or without 100 ppm CE for 1 hour. Protein expression of ZO-1 and actin filaments was detected using immunofluorescence microscopy (original magnification, ×40) with rabbit anti-ZO-1 (green) and phalloidin (red). Representative images captured from BEAS-2B cells are shown.</p

HO-1 protects CE-induced injury, permeability increase and apoptosis.

<p>HO-1 WT and HO-1 KO mice were exposed to either 20 μl of CE or held as controls for 24 hours. (A) The lung tissues were stained with H&E and images under a laser scanning microscopy. Data shown are representative of three donors. (B) Lung inflammation was detected by BAL cell counts. (C) Lung permeability was evaluated by BAL protein content. (D) The quantitative results from TUNEL assay were presented as percentage of TUNEL positive cells per field. Data are shown as a mean ± SD from three different experiments. * <i>p</i> < 0.05, ** <i>p</i> < 0.01 vs HO-1 WT (-) CE; ## <i>p</i> < 0.01 vs HO-1 KO (-) CE; && <i>p</i> < 0.01 vs HO-1 WT (+) CE by a one-way ANOVA with HSD test.</p

Upregulation of HO-1 and NOX4 in response to CE stimulation.

<p>Zebrafish were exposed to either CE 150 ppm or control for 56 hours and IHC analysis was performed for HO-1 (A) and NOX4 (B) expression. CE exposure is accomplished by holding adult zebrafish in 1 liter borosilicate class beakers (acid washed, followed with neutralizing alkali) to eliminate any potential reaction of the CE with plastic. (C) Cell lysates from BEAS-2B cells were analyzed by western blotting with anti-HO-1 and NOX4 antibodies at different concentrations of CE for 4 hours. β-actin was used as loading control. For quantification of the HO-1 and NOX4 expression, membranes were scanned and the bar graphs illustrated the relative expression of HO-1 and NOX4 by densitometry. The signal intensity for HO-1 or NOX4 at control was set to 1.0. (D) BEAS-2B cells were exposed to either CE or control for 4 hours, and HO activity was measured as pmol of bilirubin formed per mg protein per h. Data presents mean values of three independent experiments. Data are shown as a mean ± SD. ** <i>p</i> < 0.01 vs control by a one-way ANOVA with HSD test.</p